Chemical Tests

Question 1

Give the reagent, observation, reason for observation, and equation when testing for AgBr

Answer 1

• add concentrated NH3
• cream ppt dissolves
• AgBr(s) + NH3(l) –> Ag(NH3)2(aq) + Br-(aq)

Question 2

Give the reagent, observation, reason for observation, and equation when testing for CO3^2-

Answer 2

• any acid, but HNO3 is best
• effervescence
• CO2 formed
• CO3^2- + 2H+ –> CO2 + H2O

Question 3

Give the reagent, observation, reason for observation, and equation when testing for NH4+

Answer 3

• heat with NaOH
• gas released which turns damp red litmus paper blue
• ammonia gas forms/released
• NH4+ + OH- –> NH3 + H2O